Cancer is a genetically complex and biologically heterogeneous group of disorders. It has become increasingly clear that the laboratory mouse, the best genetically defined experimental model organism for humans, presents a major opportunity for rapid advancement in understanding the genetic basis and underlying biology of cancer. The overall goal for our course, Workshop on Techniques in Modeling Human Cancer in Mice, is to train a small group of young scientists (predoctoral, postdoctoral trainees, new investigators) in the use of genetically defined laboratory mice as genetic tools for asking questions about gene function and the role of genetics in the biology of cancer. Students completing the course will acquire a practical knowledge of how to characterize and analyze specific mouse cancer models. The models chosen will reflect several organ sites including colon, prostate, mammary, lung, skin, blood and brain. The course will consist of didactic lectures in the morning to introduce particular organ sites and the characteristics of cancers associated with those organ sites, followed by intensive laboratory sessions whereby students will gain hands on experience in the manipulation and analysis of relevant mouse models. Sessions will include fixed and live cell imaging techniques, cytometry, surgical approaches to the implantation of tumors, and pathology. These Aims will be accomplished by offering an intensive 10-day course to 16 young investigators chosen for their outstanding research potential. They will interact with a group of prominent mouse geneticists and cancer biologists both from The Jackson Laboratory and other prominent institutions. The size of the class will be kept deliberately small in order to achieve a desirable level of student-faculty interaction and to permit extensive laboratory training and practice for the students. The course will be held annually during the month of October at Highseas, The Jackson Laboratory's residential oceanfront conference facility. Lectures, discussions, workshops, and demonstrations will be held morning, afternoon, and evening for a total of approximately 72 hours of didactic and hands-on training. We are asking for a full five years of support in this application. The Jackson Laboratory is an NCI-designated Basic Research Cancer Center and has a long history of hosting advanced courses and scientific meetings.